STEADY-STATE CRACK GROWTH IN HYBRID FIBER METAL LAMINATES AS A TOOL FOR DESIGN

摘要

Hybrid laminate materials consisting of alternating layers of metals and fiber-reinforced composites, examples of which include Glare and CentrAl, exhibit Steady-State Crack Growth (SSCG) behavior, where the surface cracks grow at approximately constant rates, regardless of crack length, under a wide range of conditions. This paper discusses results of experiments with CentrAl showing how this phenomenon can be exploited to aid in the design and analysis of structures with more complexity than simple coupons. Tests were conducted with fatigue cracks growing through stress gradients due to modified specimen geometry and the presence of broken stiffeners. Good agreement between the crack growth rate as a function of local stresses and the crack growth rates of traditional coupon specimens as a function of global applied stresses suggests that the SSCG approach to design is appropriate for applying empirical lab-scale results of crack growth performance of hybrid laminate materials to the design of larger structure with complex load scenarios.